Gemini Observatory

The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. ''(See List of largest optical reflecting telescopes)''.

The National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, and MCTIP of Argentina own and operate the Gemini Observatory. The NSF is currently (2017) the majority partner, contributing approximately 70% of the funding needed to operate and maintain both telescopes. The operations and maintenance of the observatory is managed by the Association of Universities for Research in Astronomy (AURA), through a cooperative agreement with NSF. NSF acts as the Executive Agency on behalf of the international partners.

The Gemini telescopes house a suite of modern instruments, offer superb performance in the optical and near-infrared, and employ sophisticated adaptive optics technology to compensate for the blurring effects of the Earth's atmosphere. Gemini is a world-leader in wide-field adaptive optics assisted infrared imaging, and has recently commissioned the Gemini Planet Imager, an instrument that allows researchers to directly image and analyze exoplanets that are a millionth as bright as the host star around which they orbit. Gemini continues to support research in almost all areas of modern astronomy, including the Solar System, exoplanets, star formation and evolution, the structure and dynamics of galaxies, supermassive black holes, distant quasars, and the structure of the Universe on the largest scales.

Past participants in the Gemini Observatory include Australia and the United Kingdom. The UK dropped out of the partnership at the end of 2012 and the Gemini Observatory has responded to the loss of funding by significantly reducing its operating costs, streamlining its operations, and implementing energy savings measures at each site. Both telescopes are also now operated remotely from Base Facility Operations centers in Hilo, Hawaii, and La Serena, Chile.

Overview

The Gemini Observatory's international Headquarters and Northern Operations Center is located in Hilo, Hawaii at the University of Hawaii at Hilo University Park. The Southern Operations Center is located on the Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile.

* The "Gemini North" telescope, officially called the ''Frederick C. Gillett Gemini Telescope'' is located on Hawaii's Mauna Kea, along with many other telescopes. That location provides excellent viewing conditions due to the superb atmospheric conditions (stable, dry, and rarely cloudy) above the dormant volcano. It saw first light in 1999 and began scientific operations in 2000.
* The "Gemini South" telescope is located at over elevation on a mountain in the Chilean Andes called Cerro Pachón. Very dry air and negligible cloud cover make this another prime telescope location (again shared by several other observatories, including the Southern Astrophysical Research Telescope (SOAR) and Cerro Tololo Inter-American Observatory). Gemini South saw first light in 2000.

Together, the two telescopes cover almost all of the sky except for two areas near the celestial poles: Gemini North cannot point north of declination +89 degrees, and Gemini South cannot point south of declination −89 degrees.

Both Gemini telescopes employ a range of technologies to provide world-leading performance in optical and near-infrared astronomy, including laser guide stars, adaptive optics, multi conjugate adaptive optics, and multi-object spectroscopy. In addition, very high-quality infrared observations are possible due to the advanced protected silver coating applied to each telescope's mirrors, the small secondary mirrors in use (resulting in an f16 focal ratio), and the advanced ventilation systems installed at each site.

History

It is estimated that the two telescopes cost approximately US$187 million to construct, and a night on each Gemini telescope is worth tens of thousands of U.S. dollars.

The two 8-meter mirror blanks, each weighing over , were fabricated from Corning's Ultra Low Expansion glass. Each blank was constructed by the fusing together of and subsequent sagging of a series of smaller hexagonal pieces. This work was performed at Corning's Canton Plant facility located in upstate New York. The blanks were then transported via ship to REOSC, located south of Paris for final grinding and polishing.

One decision made during design to save money was eliminating the two Nasmyth platforms. This makes instruments like high resolution spectrographs and adaptive optics systems much more difficult to construct, due to the size and mass requirement inherent with Cassegrain instruments. A further challenge in designing large instruments is the requirement to have a specific mass and center-of-mass position to maintain the overall balance of the telescope.

UK funding crisis

In November 2007 it was announced that the UK's Science and Technology Facilities Council (STFC) had proposed that, to save £4 million annually, it would aim to leave the telescope's operating consortium. At a consortium meeting in January 2008, the conclusion was made that the UK would officially withdraw from the Gemini Partnership and the Gemini Observatory Agreement effective February 28, 2007. This decision significantly disrupted observatory budgets, and resulted in the cancellation of at least one instrument in development at that time, the Precision Radial Velocity Spectrograph.

Since the reason for the UK breaking its part of the agreement seemed to be entirely financial, there was public outcry, including the "Save Astronomy" movement which asked citizens to speak up against the astronomy budget cuts. The UK rethought their decision to withdraw from Gemini, and requested reinstatement into the agreement, and were officially welcomed back on February 27, 2008. However, in December 2009 it was announced that the UK would indeed leave the Gemini partnership in 2012, as well as terminating several other international science partnerships, due to continuing funding limitations.

Directorship

The first director of Gemini was Matt Mountain, who after holding the post for eleven years left in September 2005 to become director of Space Telescope Science Institute (STScI). He was succeeded by Jean-René Roy, who served for nine months, after which time Doug Simons held the directorship from June 2006 to May 2011. He in turn was succeeded by an interim appointment of the then-retired Fred Chaffee, former director of W. M. Keck Observatory. Chaffee was succeeded in August 2012 by Markus Kissler-Patig, who held the post until June 2017. Laura Ferrarese succeeded Dr. Kissler-Patig in July 2017 with an interim appointment. The current director is Jennifer Lotz since September 6, 2018.

Governance and oversight

The Observatory is governed by the Gemini Board, as defined by the Gemini International Agreement. The Board sets budgetary policy bounds for the Observatory and carries out broad oversight functions, with advice from a Science and Technology Advisory sub-Committee (the STAC) and a Finance sub-Committee. The U.S. holds six of the 13 voting seats on the Gemini Board. The U.S. members of the Board typically serve three year terms and are recruited and nominated by the National Science Foundation (NSF), which represents the US community in all aspects of Gemini operations and development. Gemini is currently managed by the Association of Universities for Research in Astronomy (AURA), Inc., on behalf of the partnership through an award from NSF. AURA has operated Gemini since its construction in the 1990s.

NSF serves as the Executive Agency and acts on behalf of the international participants. NSF has one seat on the Gemini Board; an additional NSF staff member serves as the Executive Secretary to the board. Programmatic management is the responsibility of an NSF Program Officer. The Program Officer monitors operations and development activities at the Observatory, nominates U.S. scientists to Gemini advisory committees, conducts reviews on behalf of the partnership, and approves funding actions, reports, and contracts.

Instrumentation

Adaptive optics

Both Gemini telescopes employ sophisticated state-of-the-art adaptive optics systems. Gemini-N routinely uses the ALTAIR system, built in Canada, which achieves a 30–45% Strehl ratio on a 22.5-arcsecond-square field and can feed NIRI, NIFS or GNIRS; it can use natural or laser guide stars. In conjunction with NIRI it was responsible for the discovery of HR8799b.

At Gemini-S the Gemini Multi-Conjugate Adaptive Optics System (GeMS) may be used with the FLAMINGOS-2 near-infrared imager and spectrometry, or the Gemini South Adaptive Optics Imager (GSAOI), which provides uniform, diffraction-limited image quality to arcminute-scale fields of view. GeMS achieved first light on December 16, 2011. Using a constellation of five laser guide stars, it achieved FWHM of 0.08 arc-seconds in H band over a field of 87 arc-seconds square.

An adaptive secondary mirror has been considered for Gemini, which would provide reasonable adaptive-optics corrections (equivalent to natural seeing at the 20th-percentile level for 80% of the time) to all instruments on the telescope to which it is attached. However, , there are no plans to implement such an upgrade to either telescope.

Instruments

In recent years the Gemini Board has directed the observatory to support only four instruments at each telescope. Because Gemini-N and Gemini-S are essentially identical, the observatory is able to move instruments between the two sites, and does so on a regular basis. Two of the most popular instruments are the Gemini Multi-Object Spectrographs (GMOS) on each of the telescopes. Built in Edinburgh, Scotland by the UK Astronomy Technology Centre, these instruments provide multi-object spectroscopy, long-slit spectroscopy, imaging, and integral field spectroscopy at optical wavelengths. The detectors in each instrument have recently been upgraded with Hamamatsu Photonics devices, which significantly improve performance in the far red part of the optical spectrum (700–1,000 nm).

Near-infrared imaging and spectroscopy are provided by the NIRI, NIFS, GNIRS, FLAMINGOS-2, and GSAOI instruments. The availability and detailed descriptions of these instruments is documented on the Gemini Observatory Web site.

One of the most exciting new instruments at Gemini is GPI, the Gemini Planet Imager. GPI was built by a consortium of US and Canadian institutions to fulfill the requirements of the ExAOC Extreme Adaptive Optics Coronagraph proposal. GPI is an extreme adaptive-optics imaging polarimeter

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